A reading method for data in a card reader including: (a) inserting a card provided with a magnetic stripe into a card insertion part, (b) reading data in the magnetic stripe with a data read section at least at a time of insertion or extraction of the card, (c) comparing an output level from the data read section with a predetermined read decision reference value, and then (d) changing the read decision reference value when the data have not been read. The read decision reference value may be changed from a low sensitivity setting to a high sensitivity setting or maybe circularly changed. The reading method for data is effectively utilized for a manual card reader.